Add spec ensuring that work_packages#index retrieves queries from session
Clear filters when selecting work packages index item and add integration test
Add copyright headers
Don't clear filters when jumping to work packages after project switch
Revert "Don't clear filters when jumping to work packages after project switch"

This reverts commit 94ade180c4c15b1f81817b729f3cff371c566748.
Currently filters are reset after project jumps in the queries_helper regardless of the set_filter parameter.
Fix unit test


Project jumps to work packages tab set the set_filter param.
Add change log entry